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This study investigated the feasibility of combined padded metatarsal cup on plantar pressures and stress distribution in the bone alignment of female foot with high heeled footwear during balanced standing. The aim of this study is to redistribute the plantar pressure away from the medial side of the forefoot. A combined padded metatarsal cup (CPMC) was developed from medium soft ethylene vinyl acetate (MSEVA) and very soft ethylene propylene diene monomer (VSEPDM) neoprene sponge. The participants of three categories were selected for the study. The peak plantar pressure and a radiographic assessment of foot musculoskeletal alignment were carried out. The results showed that the magnitude of load on medial forefoot area could be effectively reduced by inserting joint of soft materials on metatarsal region. Hence load on hallux could also be reduced satisfactorily which could resist the hallux valgus deformity. A comparison of conventional system and jointing materials separately with the developed prototype was made and found that the developed prototype of CPMC provides more relaxation of plantar pressure and musculoskeletal safety and confirms more comfort on hypothesis test. The concept of combined padded metatarsal cup should therefore be considered to help in designing musculoskeletal safety footwear.

To evaluate the rotational change in the first metatarsal bone (1MT) of the foot during natural standing using an upright computed tomography (CT) scanner with 320-detector rows. A total of 52 feet of 28 asymptomatic subjects (aged 23-39 years) were evaluated in the natural standing position with or without weight-bearing. A foot pressure plate was used to determine the non-weight-bearing (NWB) or single leg full-weight-bearing (s-FWB) conditions. CT examinations were performed using a noise index of 15 for a slice thickness of 5 mm, rotation speed of 0.5 sec, and slice thickness of 0.5 mm. The rotation of the 1MT was measured on the coronal CT image, which cut the sesamoids' bellies in the frontal slide of the first metatarsal and sesamoids perpendicular to the longitudinal bisection of the third metatarsal, and compared between the weight-bearing conditions. Intra- and inter-observer reliabilities of the rotation angle were also evaluated. The intra- and inter-observer correlation coefficients were 0.961 and 0.934, respectively. The 1MT pronation angle was significantly greater in the s-FWB condition than in the NWB condition (15.2° ± 5.4° vs. 12.5° ± 5.3°, P < 0.01). No sex difference was found in the magnitude of the 1MT pronation angle as a result of weight-bearing. This study first demonstrated that pronation of 1MT occurs due to natural full-weight-bearing in asymptomatic feet. The 1MT's rotational movement under weight-bearing conditions may relate to the onset and pathogenesis of the hallux valgus. Clin. Anat. 32:715-721, 2019. © 2019 Wiley Periodicals, Inc., (© 2019 Wiley Periodicals, Inc.)

Due to the limitations of experimental approaches, comparison of the internal deformation and stresses of the human man foot between forefoot and rearfoot landing is not fully established. The objective of this work is to develop an effective FE modelling approach to comparatively study the stresses and energy in the foot during forefoot strike (FS) and rearfoot strike (RS). The stress level and rate of stress increase in the Metatarsals are established and the injury risk between these two landing styles is evaluated and discussed. A detailed subject specific FE foot model is developed and validated. A hexahedral dominated meshing scheme was applied on the surface of the foot bones and skin. An explicit solver (Abaqus/Explicit) was used to stimulate the transient landing process. The deformation and internal energy of the foot and stresses in the metatarsals are comparatively investigated. The results for forefoot strike tests showed an overall higher average stress level in the metatarsals during the entire landing cycle than that for rearfoot strike. The increase rate of the metatarsal stress from the 0.5 body weight (BW) to 2 BW load point is 30.76% for forefoot strike and 21.39% for rearfoot strike. The maximum rate of stress increase among the five metatarsals is observed on the 1st metatarsal in both landing modes. The results indicate that high stress level during forefoot landing phase may increase potential of metatarsal injuries., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Most in-vivo indentation techniques are limited by the lack of adequate indentation into the plantar soft tissue. The purpose of this study is therefore to assess the effect of deformation depth on plantar soft tissue behavior and to establish a guideline for the minimum indentation depth that is sufficient to quantify critical plantar soft tissue behavior. Twenty young subjects (20-25 years) participated in this study. The test was conducted with equal weight borne on each of the participants׳ feet to mimic the static stance of the gait cycle. During the experiment, the indenter probed the 2nd sub-metatarsal head (MTH) and heel pad tissue at a constant rate of 12.3 mm/s. The maximum tissue deformation induced was varied from 1.2 mm to 6.0 mm, in steps of 1.2 mm. The tissue stiffness obtained from the tissue response curves was compared and fitted to the proposed viscoelastic model. As the probe tip indents deeper into the plantar soft tissue beyond a threshold depth, Xs, the force gradient increases notably. The absolute value of Xs was approximately 2.23 mm and 2.14 mm at the heel and 2nd sub-MTH respectively. Indentation depths which were less than this threshold depth might not be representative of the nature of plantar soft tissue nor reflect the critical deformation it experiences during physical activities that expose the tissue to risk of ulceration. Our study indicated the necessity to induce a minimum tissue indentation depth in order to describe its actual characteristics. By doing so, additional useful parameters can be obtained to identify potentially abnormal soft tissue., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: We measured loading forces across different points of the plantar foot surface to examine how different types of casts affect load distribution through the foot and ankle. The patella tendon-bearing (PTB) or Sarmiento cast is the current "gold-standard" casting method for offloading force through the foot and ankle. We aimed to determine if a rocker bottom frame attached to a below-knee cast (Beagle Böhler Walker) would be as effective or better at reducing load distribution during full weightbearing., Method: We applied TekScan FlexiForce A201 force sensors to the first and fifth metatarsal heads and the plantar surface of the calcaneus of 14 healthy volunteers. All volunteers had force measurements taken without a cast applied and then with a traditional Sarmiento cast, a standard below-knee cast, and a below-knee cast with the Böhler Walker frame fitted., Results: Compared with a standard below-knee cast, the Böhler Walker frame reduced the mean peak force through the head of the first metatarsal by 58.9% (P < .0001), 73.1% through the head of the fifth metatarsal (P < .0001), and 32.2% (P < .0001) through the calcaneus. The Sarmiento cast demonstrated a mean percentage reduction in peak force of 8.6% (P = .39) and 4.4% (P = .87) through the first and fifth metatarsal heads, respectively, but increased the mean peak force by 5.9% (P = .54) through the calcaneus., Conclusion: Using a Böhler Walker frame applied to a below-knee cast significantly reduced weight transfer through the foot compared with a Sarmiento cast or standard below-knee cast., Clinical Relevance: This reduction in force through the foot could mean early weightbearing would be safer in patients with a wide variety of foot and ankle pathologies such as ankle fractures or operative fixations. This may reduce the incidence of immobility-dependent morbidity., (© The Author(s) 2015.)

Material properties of the plantar soft tissue have not been well quantified in vivo (i.e., from life subjects) nor for areas other than the heel pad. This study explored an in vivo investigation of the plantar soft tissue material behavior under the metatarsal head (MTH). We used a novel device collecting indentation data at controlled metatarsophalangeal joint angles. Combined with inverse analysis, tissues׳ joint-angle dependent material properties were identified. The results showed that the soft tissue under MTH exhibited joint-angle dependent material responses, and the computed parameters using the Ogden material model were 51.3% and 30.9% larger in the dorsiflexed than in the neutral positions, respectively. Using derived parameters in subject-specific foot finite element models revealed only those models that used tissues׳ joint-dependent responses could reproduce the known plantar pressure pattern under the MTH. It is suggested that, to further improve specificity of the personalized foot finite element models, quantitative mechanical properties of the tissue inclusive of the effects of metatarsophalangeal joint dorsiflexion are needed., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Context: Stress fractures are one of the most common injuries in sports, accounting for approximately 10% of all overuse injuries. Treatment of fifth metatarsal stress fractures involves both surgical and nonsurgical interventions. Fifth metatarsal stress fractures are difficult to treat because of the risks of delayed union, nonunion, and recurrent injuries. Most of these injuries occur during agility tasks, such as those performed in soccer, basketball, and lacrosse., Objective: To examine the effect of a rigid carbon graphite footplate on plantar loading during 2 agility tasks., Design: Crossover study., Setting: Laboratory., Patients or Other Participants: A total of 19 recreational male athletes with no history of lower extremity injury in the past 6 months and no previous metatarsal stress fractures were tested., Main Outcome Measure(s): Seven 45° side-cut and crossover-cut tasks were completed in a shoe with or without a full-length rigid carbon plate. Testing order between the shoe conditions and the 2 cutting tasks was randomized. Plantar-loading data were recorded using instrumented insoles. Peak pressure, maximum force, force-time integral, and contact area beneath the total foot, the medial and lateral midfoot, and the medial, middle, and lateral forefoot were analyzed. A series of paired t tests was used to examine differences between the footwear conditions (carbon graphite footplate, shod) for both cutting tasks independently (α = .05)., Results: During the side-cut task, the footplate increased total foot and lateral midfoot peak pressures while decreasing contact area and lateral midfoot force-time integral. During the crossover-cut task, the footplate increased total foot and lateral midfoot peak pressure and lateral forefoot force-time integral while decreasing total and lateral forefoot contact area., Conclusions: Although a rigid carbon graphite footplate altered some aspects of the plantar-pressure profile during cutting in uninjured participants, it was ineffective in reducing plantar loading beneath the fifth metatarsal.

Background: In pes cavus, the medial longitudinal arch elevation reduces the contact surface area and consequently increases the corresponding plantar pressure measurements. This poor distribution of loads may produce associated pathology and pain in this or other areas of the body. Normal reference values need to be established in order to determine which patterns are prone to pathology., Objectives: To compare the plantar pressures and weight-bearing surface in a population with pes cavus to a population with neutral feet., Method: The sample comprised 68 adults, 34 with pes cavus and 34 with neutral feet. The Footscan USB Gait Clinical System(®) was used as a platform to measure the total contact area and plantar pressure under the forefoot, midfoot, hindfoot, each metatarsal head, and the overall metatarsal area. A statistical analysis of the data was performed using Student's t-test for independent samples., Results: The pes cavus subjects showed a significant reduction in their weight-bearing area [neutral feet: 165.04 ( ± 20.68) cm(2); pes cavus: 118.26 ( ± 30.31) cm(2); p < 0.001] and significantly increased pressures under all zones of the forefoot except the fifth metatarsal [metatarsal pressure: in neutral feet 503,797 ( ± 9.32) kPa; in pes cavus 656.12 ( ± 22.39) kPa; p < 0.001]., Conclusions: Compared to neutral feet, pes cavus feet show a reduction in total contact surface and the load under the first toe. A significant increase is present in the load under the metatarsal areas, but the relative distribution of this load is similar in both groups., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Fifth metatarsal stress fractures are common in sports and often result in delayed and non-union. The purpose of this study was to examine the effect of a rigid carbon graphite footplate (CGF) on plantar loading during take-off and landing from a jump. Nineteen recreational male athletes with no history of lower extremity injury in the past 6 months and no foot or ankle surgery in the past 3 years participated in this study. Subjects completed 7 jumping tasks while wearing a standard running shoe and then the shoe plus the CGF while plantar loading data was recorded. A series of paired t-tests were used to examine differences between the two footwear conditions independently for both takeoff and landing (a = 0.05). The contact area in the medial midfoot (p < .001) and forefoot (p = .010) statistically decreased when wearing the CGFP. The force–time integral was significantly greater when wearing the CGFP in the middle (p < .001) and lateral forefoot (p = .019). Maximum force was significantly greater beneath the middle (p < .001) and lateral forefoot (p < .001) when wearing the CGFP, while it was decreased beneath the medial midfoot (p < .001). During landing, the contact area beneath the medial (p = .017) and lateral midfoot (p = .004) were significantly decreased when wearing the CGFP. The force– time integral was significantly decrease beneath the medial midfoot (p < .001) when wearing the CGFP. The maximum force was significantly greater beneath the medial (p = .047) and middle forefoot (p = .001) when the subject was wearing the CGFP. The maximum force beneath the medial midfoot (p < .001) was significantly reduced when wearing the carbon graphite footplate. The results of the study indicate that the CGF is ineffective at reducing plantar loading during jumping and landing.

Forefoot pain is a common problem in older people. We determined whether plantar pressures during gait and the relative lengths of the lesser metatarsals differ between older people with and without plantar forefoot pain. Dynamic plantar pressure assessment during walking was undertaken using the Tekscan MatScan® system in 118 community-dwelling older people (44 males and 74 females), mean age 74 (standard deviation=5.9) years, 43 (36%) of whom reported current or previous plantar forefoot pain. The relative lengths of metatarsals 1-5 were determined from weightbearing X-rays. Participants with current or previous plantar forefoot pain exhibited significantly (p=0.032) greater peak plantar pressure under metatarsal heads 3-5 (1.93 ± 0.41 kg/cm(2) vs. 1.74 ± 0.48 kg/cm(2) ). However, no differences were found in relative metatarsal lengths between the groups. These findings indicate that older people with forefoot pain generate higher peak plantar pressures under the lateral metatarsal heads when walking, but do not exhibit relatively longer lesser metatarsals. Other factors may be responsible for the observed pressure increase, such as reduced range of motion of the metatarsophalangeal joints and increased stiffness of plantar soft tissues., (Copyright © 2012 Orthopaedic Research Society.)

Background: Metatarsal supports are effective at decreasing plantar foot pressures at the metatarsal heads, however, little is known about the dependence of this decrease upon height and position., Methods: Barefoot static stance pressure measurements were recorded during standing in single limb support (n=22). Two metatarsal support heights (5mm, 10mm) were evaluated in six positions at 5mm increments (0, 5, 10, 15, 20, 25 mm) proximal to the metatarsal heads along the longitudinal axis of the foot. The barefoot condition with no metatarsal support served as the control. Mean force was measured for each test condition. The findings of this study are limited to the barefoot (unshod) condition., Findings: Mean plantar force decreased significantly under the second metatarsal head with both 5 and 10mm metatarsal supports compared to the control, and 10mm metatarsal support compared with 5mm metatarsal support (P<0.05) while no statistically significant differences were noted relative to longitudinal axis position., Interpretation: The results of this study suggest that the thickness of a metatarsal support is a determinant factor in regulating plantar loading. Surprisingly, the longitudinal axis location of a metatarsal support does not appear to be as important as clinically presumed since the data showed that the force decrease was similar for all positions from 5 to 25 mm. Thus, the orthotic induced effect of a metatarsal support seems to have a sizable interaction range that has not previously been reported. We speculate that the metatarsal support's fulcrum and lift effect can be sustained at a more proximal position due to the foot's rigidity as a lever and the manner in which a metatarsal support interacts with the plantar aponeurosis.

Our hypothesis in this study was that significant forces act on the fifth metatarsal during certain maneuvers commonly performed while playing basketball and that medial arch support influences these forces. Eleven male collegiate basketball players participated in this study. Electronic pressure sensors capable of dynamic readings were inserted into the players' shoes, and surface electromyographic (EMG) electrodes were placed over the peroneus longus and brevis muscles. The players performed 3 common maneuvers postulated to place maximal stress on the fifth metatarsal. The maneuvers were performed in a standard basketball shoe, then in a shoe with an orthosis supporting the arch. During each of these maneuvers, EMG activity of the ankle everters was recorded, along with maximal force, total work, and time elapsed beneath the fifth metatarsal.

The introduction of the M90 boot with a more flexible outer sole to military recruits in Sweden was accompanied by an increase in second metatarsal stress fractures. This study compared the new boot with the previous, stiffer model. A combination of external plantar pressure measurement (two subjects) and an in vivo measurement of dorsal metatarsal strain (six subjects) using strain gauge instrumented staples was implemented. Walking in both boot models resulted in increased plantar pressure under the heads of the lesser metatarsals and generally decreased loading under the remainder of the foot. Dorsal metatarsal tension increased for subjects wearing the new boot throughout a walking protocol.

Articular hyaline cartilage takes on the contours of the subchondral bone on which it lies, but its thickness varies between joints, within a single joint and within a single articular surface. Previous studies have correlated articular cartilage thickness distribution with the degree of stress and weight bearing on joint surfaces, but few studies have considered the thickness of the calcified cartilage in relation to these parameters. Here we report a correlation between the cartilage thickness distribution and weight bearing distribution on the head of the 1st metatarsal bone, a component of one of the major weight bearing joints in the lower extremity during the gait cycle. The greatest total and uncalcified articular cartilage thickness was found on the central and lateral distal aspects of the metatarsal head, a region that receives maximal ground reactive force during the propulsive phase of the normal gait cycle. Although the thickness of the calcified cartilage was correlated with the thickness of the uncalcified cartilage, it varied to a lesser extent across the articular surface than did that of the uncalcified cartilage.

A technique is introduced for the measurement of plantar soft tissue thickness during barefoot walking. Subjects stepped into an adjustable Plexiglas frame which ensured that the required bony landmarks were appropriately positioned relative to a linear ultrasound probe connected to a conventional 7.5 MHz ultrasound scanner. Clear images of the metatarsal condyles or other foot bones were obtained throughout ground contact. Subsequent analysis of the video taped images using a motion analysis system allowed the tissue displacement to be calculated as a function of time. The tissue underneath the second metatarsal head was shown to undergo an average maximum compression of 45.7% during the late stages of ground contact during first step gait in a group of five normal subjects with a mean unloaded tissue thickness of 15.2 mm. The technique has a number of applications, including use in the validation of deformation predicted by finite element models of the soft tissue of the foot, and the study of alterations in the cushioning properties of the heel by devices which constrain the displacement of the heel pad.

The effect of mechanical stresses on osteogenesis, the viability of osteocytes and their metabolic activity in organ culture of bones intermittently loaded "in vitro" are reported. Metatarsal bones, isolated from 12-day-old rats, were cultured in BGJb medium (with 10% foetal calf serum, 75 micrograms/ml of ascorbic acid, 100 U/ml of penicillin and 100 micrograms/ml of streptomycin), in humidified air enriched by 5% CO2 and 30% O2, and loaded in our original device for 1/2 an hour at 1 Hz. homotypic isolated and unloaded bones, cultured in the same medium, were taken as controls. The ALP (alkaline phophatase activity) increases in the media of loaded bones in comparison with the control bones. The percentage of viable osteocytes is significantly greater in loaded than in control bones. TEM observations demonstrate that in both loaded and control unloaded bones, osteocytes show well developed organelle machinery and several gap junctions with adjacent cellular processes. In the cells of loaded bones, however, a higher number of cytoplasmic organelles and gap junctions were found. In particular, RER increases twice, gap junctions three times. The induced osteogenesis and the TEM observations demonstrate the suitability of this experimental model and support the recent advanced hypothesis according to which the mechanical loading may exert a trophic function on osteocytes, stimulating both the proteic synthesis in the above-mentioned cells and the cell-to-cell communication. Furthermore, the loading is likely to exert a biological stimulus on osteoblasts via signalling molecules produced by osteocytes.